Rod guides are intended to prevent a sucker rod which drives a downhole pump from rubbing against interior walls of the production tubing. U.S. Pat. No. 5,339,896 which issued to J. M. Huber Corporation in 1994 is representative of the type of rod guide currently in widespread use. The rod guide has a flexible body that is generally "C" shaped in cross-section. An elongate slot extends the length of the body, by means of which the guide is installed on a sucker rod. The width of the slot is less that the outer diameter of the sucker rod. During installation, the slot is expanded by flexing the flexible body to snap the body around the sucker rod. The body has a plurality of radial vanes which serve to centralize the sucker rod, while minimizing flow resistance around the guide. The body rides on the sucker rod between two stops which maintain axial positioning. Canadian Patent 2,101,677 by Sable which was published in 1994 discloses a rod guide with a more complex slot configuration. There is provided a body with two diametrically opposed longitudinal slots each of which extend half the length of the rod guide. A transverse slot connects the two longitudinal slots, by manipulating the body the rod guide can be snapped onto a sucker rod.
The rod guides, as described above, are experiencing problems with wear due to abrasion. Fine grains of sand and like particulate matter are working their way past the stops and getting between the rod guide and the sucker rod.